Nereus

From Tardis Wiki, the free Doctor Who reference

Nereus was the father of Amphitrite and the grandfather of Galatea.

On 20 October 1901, Nereus was spying on the Lankester. He killed a crew member, Crawford, to avoid being seen. He swam through a breach in the ship and spied on the Sixth Doctor and Callany. He brought the Doctor down into his realm and returned his TARDIS.

Nereus returned to the ship and, with his people, killed Jacques De Requin. He then collected Galatea from the Doctor and Peri Brown. (AUDIO: Cryptobiosis)